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From:   Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
Date:   Thu, 19 Mar 2020 14:57:07 +0200
Message-ID: <CAGgjyvFebxXaKkhy-UR1-kaYWozpP67YtVf5mp4mTHFQRhsjKg@mail.gmail.com>
Subject: Re: [RFC PATCH 1/7] pwm: rename the PWM_POLARITY_INVERSED enum
To:     =?UTF-8?Q?Uwe_Kleine=2DK=C3=B6nig?= 
        <u.kleine-koenig@pengutronix.de>
Cc:     Thierry Reding <thierry.reding@gmail.com>,
        devicetree@vger.kernel.org, linux-pwm@vger.kernel.org,
        Paul Barker <pbarker@konsulko.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Marcel Ziswiler <marcel.ziswiler@toradex.com>,
        Igor Opaniuk <igor.opaniuk@toradex.com>,
        Philippe Schenker <philippe.schenker@toradex.com>,
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        Chen-Yu Tsai <wens@csie.org>,
        Claudiu Beznea <claudiu.beznea@microchip.com>,
        Fabio Estevam <festevam@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Heiko Stuebner <heiko@sntech.de>,
        Kevin Hilman <khilman@baylibre.com>,
        Ludovic Desroches <ludovic.desroches@microchip.com>,
        Maxime Ripard <mripard@kernel.org>,
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On Thu, Mar 19, 2020 at 2:11 PM Uwe Kleine-K=C3=B6nig
<u.kleine-koenig@pengutronix.de> wrote:
>
> Hello,
>
> [dropping Tony Prisk <linux@prisktech.co.nz> from recipients]
>
> On Thu, Mar 19, 2020 at 01:40:28PM +0200, Oleksandr Suvorov wrote:
> > Thierry, I see the PWM core converts the bit field "third cell" into
> > the polarity variable.
> > Now I probably understand your sight and agree that we shouldn't give
> > the same names to bits in bitfield (dts) and values of a variable.
> >
> > But there are lots of useless "0" values of third cell of "pwms"
> > option in dts files.
> >
> > I see 2 ways now:
> > - just remove all "0" "third cell" from "pwms" options in dts files. I
> > see this "0" confuses some people.
>
> Then you have to overwrite pwm-cells of the provider. If there are two
> PWMs used from the same provider and only one is inverted this won't
> work. (Not entirely sure I understood your suggestion.) So I don't like
> this suggestion.

Good point, agree. But we still have the unnamed "0".

What about renaming the dt-bindings macro PWM_POLARITY_INVERTED
and add the new one for the normal polarity?
Like PWM_FLAG_POLARITY_NORMAL / PWM_FLAG_POLARITY_INVERTED or
DT_PWM_POLARITY_NORMAL / DT_PWM_POLARITY_INVERTED?

Using different prefix will prevent interfering names of enum and
macros in the future
and will allow using the named nop-flag PWM_FLAG_POLARITY_NORMAL in dts.

> And also in my eyes this isn't clearer, just more complicated to use.
>
> > - convert pwm_state.polarity into pwm_state.flags and use bitfield
> >   directly from dtb.
> >   It simplifies the parsing logic and makes adding new flags easier.
>
> *shrug*, I don't care much.
>
> Best regards
> Uwe
>
> --
> Pengutronix e.K.                           | Uwe Kleine-K=C3=B6nig       =
     |
> Industrial Linux Solutions                 | https://www.pengutronix.de/ =
|


--=20
Best regards
Oleksandr Suvorov

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